In the UNIX operating system, the contents of a directory may be obtained by using the "ls" command. The ls command causes the directory files and subdirectories to be displayed in a list fashion, with no graphical indication of subdirectory hierarchical structures. The listing obtained using the ls command requires some knowledge of the ls command and the symbolic characters used in the resultant output in order to decipher the directory structure. Further, navigation in the directory and subdirectories requires less intuitive keyboard entry by the users. The typical change directory command, "cd", and the path name of the file or subdirectory must be entered via the keyboard to navigate to each subdirectory level.